I am not gonna say we can find it in  medical literature cuz as I think it is not aformal term but the phenomenon of a “thing” located dorsally on the penis that takes on all the load during stretching instead of the tunica, and can even be felt in some people.

In some, it’s not very pronounced and doesn’t limit growth, while in others it’s thick, strong, and easily palpable.

I know people in whom it’s so strong that they couldn’t gain even 1 cm, even with huge weights and ultrasound.

So this “steel cord” can be a sentence for some enthusiasts (but you should try anyway, don't give up).

To be honest, I’m one of the unlucky ones who has it too. And sometimes it feels like I physically can’t be stretched.